<?xml version="1.0" encoding="utf-8"?>
<!--Generated by DFIN XBRL Instance Document - http://www.dfinsolutions.com/ - Version R3.0 - on 22-December-2024 [09:28:16] {AM}-->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
<roleRef xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedLabel" roleURI="http://www.xbrl.org/2009/role/negatedLabel" />
<roleRef xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodEndLabel" roleURI="http://www.xbrl.org/2009/role/negatedPeriodEndLabel" />
<roleRef xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedPeriodStartLabel" roleURI="http://www.xbrl.org/2009/role/negatedPeriodStartLabel" />
<roleRef xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTotalLabel" roleURI="http://www.xbrl.org/2009/role/negatedTotalLabel" />
<roleRef xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedNetLabel" roleURI="http://www.xbrl.org/2009/role/negatedNetLabel" />
<roleRef xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTerseLabel" roleURI="http://www.xbrl.org/2009/role/negatedTerseLabel" />
<roleRef xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd#netLabel" roleURI="http://www.xbrl.org/2009/role/netLabel" />
<labelLink xlink:type="extended" xlink:role="http://www.xbrl.org/2003/role/link">
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_ChangingDistributionLevelAndReturnOfCapitalRiskMember" xlink:label="loc_jhit_ChangingDistributionLevelAndReturnOfCapitalRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_ChangingDistributionLevelAndReturnOfCapitalRiskMember" xml:lang="en-US">Changing distribution level And return of capital risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_ChangingDistributionLevelAndReturnOfCapitalRiskMember" xlink:to="lab_jhit_ChangingDistributionLevelAndReturnOfCapitalRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_CreditAndCounterpartyRiskMember" xlink:label="loc_jhit_CreditAndCounterpartyRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_CreditAndCounterpartyRiskMember" xml:lang="en-US">Credit and counterparty risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_CreditAndCounterpartyRiskMember" xlink:to="lab_jhit_CreditAndCounterpartyRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_EconomicAndMarketEventsRiskMember" xlink:label="loc_jhit_EconomicAndMarketEventsRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_EconomicAndMarketEventsRiskMember" xml:lang="en-US">Economic and market events risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_EconomicAndMarketEventsRiskMember" xlink:to="lab_jhit_EconomicAndMarketEventsRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_EquitySecuritiesRiskMember" xlink:label="loc_jhit_EquitySecuritiesRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_EquitySecuritiesRiskMember" xml:lang="en-US">Equity securities risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_EquitySecuritiesRiskMember" xlink:to="lab_jhit_EquitySecuritiesRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_ESGintegrationriskMember" xlink:label="loc_jhit_ESGintegrationriskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_ESGintegrationriskMember" xml:lang="en-US">ESG integration risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_ESGintegrationriskMember" xlink:to="lab_jhit_ESGintegrationriskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_FixedIncomeSecuritiesRiskMember" xlink:label="loc_jhit_FixedIncomeSecuritiesRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_FixedIncomeSecuritiesRiskMember" xml:lang="en-US">Fixed income securities risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_FixedIncomeSecuritiesRiskMember" xlink:to="lab_jhit_FixedIncomeSecuritiesRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_ForeignSecuritiesRiskMember" xlink:label="loc_jhit_ForeignSecuritiesRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_ForeignSecuritiesRiskMember" xml:lang="en-US">Foreign securities risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_ForeignSecuritiesRiskMember" xlink:to="lab_jhit_ForeignSecuritiesRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_HedgingDerivativesAndOtherStrategicTransactionsRiskMember" xlink:label="loc_jhit_HedgingDerivativesAndOtherStrategicTransactionsRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_HedgingDerivativesAndOtherStrategicTransactionsRiskMember" xml:lang="en-US">Hedging, derivatives, and other strategic transactions risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_HedgingDerivativesAndOtherStrategicTransactionsRiskMember" xlink:to="lab_jhit_HedgingDerivativesAndOtherStrategicTransactionsRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_IlliquidAndRestrictedSecuritiesRiskMember" xlink:label="loc_jhit_IlliquidAndRestrictedSecuritiesRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_IlliquidAndRestrictedSecuritiesRiskMember" xml:lang="en-US">Illiquid and restricted securities risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_IlliquidAndRestrictedSecuritiesRiskMember" xlink:to="lab_jhit_IlliquidAndRestrictedSecuritiesRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_LeveragingRiskMember" xlink:label="loc_jhit_LeveragingRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_LeveragingRiskMember" xml:lang="en-US">Leveraging risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_LeveragingRiskMember" xlink:to="lab_jhit_LeveragingRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_LiquidityRiskMember" xlink:label="loc_jhit_LiquidityRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_LiquidityRiskMember" xml:lang="en-US">Liquidity risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_LiquidityRiskMember" xlink:to="lab_jhit_LiquidityRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_LowerRatedAndHighYieldFixedIncomeSecuritiesRiskMember" xlink:label="loc_jhit_LowerRatedAndHighYieldFixedIncomeSecuritiesRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_LowerRatedAndHighYieldFixedIncomeSecuritiesRiskMember" xml:lang="en-US">Lower rated and high yield fixed income securities risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_LowerRatedAndHighYieldFixedIncomeSecuritiesRiskMember" xlink:to="lab_jhit_LowerRatedAndHighYieldFixedIncomeSecuritiesRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_MortgageBackedAndAssetBackedSecuritiesRiskMember" xlink:label="loc_jhit_MortgageBackedAndAssetBackedSecuritiesRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_MortgageBackedAndAssetBackedSecuritiesRiskMember" xml:lang="en-US">Mortgage backed and asset backed securities risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_MortgageBackedAndAssetBackedSecuritiesRiskMember" xlink:to="lab_jhit_MortgageBackedAndAssetBackedSecuritiesRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_OperationalandcybersecurityRiskMember" xlink:label="loc_jhit_OperationalandcybersecurityRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_OperationalandcybersecurityRiskMember" xml:lang="en-US">Operational and cybersecurity Risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_OperationalandcybersecurityRiskMember" xlink:to="lab_jhit_OperationalandcybersecurityRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_PreferredAndConvertibleSecuritiesRiskMember" xlink:label="loc_jhit_PreferredAndConvertibleSecuritiesRiskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_PreferredAndConvertibleSecuritiesRiskMember" xml:lang="en-US">Preferred and convertible securities risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_PreferredAndConvertibleSecuritiesRiskMember" xlink:to="lab_jhit_PreferredAndConvertibleSecuritiesRiskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_USGovernmentagencyobligationsriskMember" xlink:label="loc_jhit_USGovernmentagencyobligationsriskMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_USGovernmentagencyobligationsriskMember" xml:lang="en-US">U S Government agency obligations risk [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_USGovernmentagencyobligationsriskMember" xlink:to="lab_jhit_USGovernmentagencyobligationsriskMember" />
<loc xlink:type="locator" xlink:href="jhit-20241031.xsd#jhit_CommonSharesMember" xlink:label="loc_jhit_CommonSharesMember" />
<label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_jhit_CommonSharesMember" xml:lang="en-US">Common Shares [Member]</label>
<labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_jhit_CommonSharesMember" xlink:to="lab_jhit_CommonSharesMember" />
</labelLink>
</linkbase>
